Reading these bits returns the contents of the Receive Data register. The register must be read only when the Receive Complete Interrupt Flag bit in the Interrupt Flag Status and Clear register (INTFLAG.RXC) is set. The status bits in STATUS must be read before reading the DATA value to get any corresponding error.
Writing these bits writes the Transmit Data register. This register must be written only when the Data Register Empty Interrupt Flag bit in the Interrupt Flag Status and Clear register (INTFLAG.DRE) is set.
Reads and writes are 32-bit or CTLB.CHSIZE based on the CTRLC.DATA32B setting.